Download Quantum Physics and Theology

Quantum Physics
and Theology
An Unexpected Kinship
JOHN POLKINGHORNE
Yale University Press
New Haven and London
Contents
Preface
ix
Acknowledgements
xv
chapter one: The Search for Truth
1
chapter two: Comparative Heuristics
23
chapter three: Lessons from History
48
chapter four: Conceptual Exploration
73
chapter five: Cousins
105
Index
111
CHAPTER ONE
The Search for Truth
eople sometimes think that it is odd,
or even disingenuous, for a person to
be both a physicist and a priest. It induces in them the same sort of quizzical surprise that would greet the
claim to be a vegetarian butcher. Yet
to someone like myself who is both a
scientist and a Christian, it seems to be a natural and harmonious combination. The basic reason is simply that science and
theology are both concerned with the search for truth. In consequence, they complement each other rather than contrast
one another. Of course, the two disciplines focus on different
dimensions of truth, but they share a common conviction that
there is truth to be sought. Although in both kinds of enquiry
this truth will never be grasped totally and exhaustively, it can
be approximated to in an intellectually satisfying manner that
deserves the adjective ‘verisimilitudinous’, even if it does not
qualify to be described in an absolute sense as ‘complete’.
Certain philosophical critiques notwithstanding, the pur1
THE SEARCH FOR TRUTH
suit of truthful knowledge is a widely accepted goal in the
scientific community. Scientists believe that they can gain
an understanding of the physical world that will prove to be
reliable and persuasively insightful within the defined limits
of a well-winnowed domain. The idea that nuclear matter is
composed of quarks and gluons is unlikely to be the very
last word in fundamental physics—maybe the speculations of
the string theorists will prove to be correct, and the quarks,
currently treated as basic constituents, will themselves turn
out eventually to be manifestations of the properties of very
much smaller loops vibrating in an extended multidimensional
spacetime—but quark theory is surely a reliable picture of the
behaviour of matter encountered on a certain scale of detailed
structure, and it provides us with a verisimilitudinous account
at that level.
Theologians entertain similar aspirations. While the infinite reality of God will always elude being totally confined within the finite limits of human reason, the theologians believe that the divine nature has been revealed to
us in manners accessible to human understanding, so that
these self-manifestations of deity provide a reliable guide to
the Creator’s relationship with creatures and to God’s intentions for ultimate human fulfilment. For the Christian,
this divine self-revelation centres on the history of Israel and
the life, death and resurrection of Jesus Christ, foundational
events that are the basis for continuing reflection and exploration within the Church, an activity that the community of
the faithful believes to be undertaken under the guidance of
the Holy Spirit. Revelation is not a matter of unchallengeable propositions mysteriously conveyed for the unquestioning acceptance of believers, but it is the record of unique
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and uniquely significant events of divine disclosure that form
an indispensable part of the rational motivation for religious
belief.
Both these sets of claims for truth-bearing enquiry are
made in conscious conflict with much of the intellectual temper of our time. In many parts of the academy the movement broadly called postmodernism holds sway. It emphasises
what it sees as the uncertain basis of human knowledge, a
vulnerability to challenge that results from the inescapable
particularity of perspective imposed by the need to interpret
experience before it can become intelligible and interesting.
The necessary cultural context of language is held to imply
that there is no universal discourse, but only a babble of local
dialects. The grand modernist programme of the Enlightenment, alleged to be based on access to clear and certain
ideas that are unquestionably acknowledged to be universally
valid, is asserted to have been no more than the imposition
of the perspective of white male Western thinkers, treated as
if such attitudes were a non-negotiable rule for all. According to postmodernism, casting off these modernist shackles
liberates twenty-first-century thinkers into being able to accept a creative plurality of ideas, thereby enabling participation in a conversation in which nobody’s opinion has a preferred priority.
We certainly need to acknowledge that rational discourse
is a more subtle matter than Enlightenment thinkers were able
to recognise. Yet in the eyes of its practitioners, science does
not at all look like a free market in ideas of an eclectic kind. We
shall attempt to specify its character in more detail shortly, but
one must begin by considering how it actually progresses. The
more extreme postmodernists would challenge the use of that
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last verb, but can one really suppose that the concepts of the
helical structure of DNA and the quark structure of matter
do not represent clear advances in understanding, intellectual gains that have become a persisting part of our understanding of the world? These ideas evolved under the irresistible nudge of nature, and not as fanciful notions whimsically
adopted by the invisible colleges of molecular biologists and
particle physicists respectively. Once the famous X-ray photographs taken by Rosalind Franklin had been seen and understood, there could be no doubt that DNA was a double helix.
Once the data on hadronic structure (the patterns found in the
properties of particles that make up nuclear matter), and the
results of deep inelastic scattering (a particularly penetrating
experimental probe), had been collected and assessed, there
could be no doubt that fractionally charged constituents lay
within protons and neutrons. Of course, interpretation was
necessary—raw data such as marks on photographic plates are
too dumb to speak of structure directly—but the naturalness
of the interpretation, and its confirmation through a continuing ability to yield more understanding in the course of further lengthy investigations, is sufficient to convince scientists
of the verisimilitudinous character of their theories. It is difficult for those not involved in scientific research to appreciate
how difficult it is to discover theories that yield persistently
fruitful and elegantly economic understanding of extensive
swathes of experimental data, and therefore how persuasive
such understandings are when they are attained. For those of
us who were privileged to be members of the particle physics
community during its twenty-five-year struggle to understand
nuclear matter—an activity that eventually led to the Stan-
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dard Model of quark theory 1—the enterprise had precisely
this convincing character. The experimentally driven investigation, often proceeding in directions quite different from
the prior expectations of the theorists, was no indulgence in
the construction of pleasing patterns, but it was the hard-won
recognition of an order in nature that is actually there.
A just account of science lies, in fact, somewhere between
the two extremes of a modernist belief in a direct and unproblematic access to clear and certain physical ideas, and a
postmodernist indulgence in the notion of an à la carte physics. The intertwining of theory and experiment, inextricably
linked by the need to interpret experimental data, does indeed imply that there is an unavoidable degree of circularity
involved in scientific reasoning. This means that the nature of
science is something more subtle and rationally delicate than
simply ineluctable deduction from unquestionable fact. A degree of intellectual daring is required, which means that ultimately the aspiration to write about the logic of scientific discovery proves to be a misplaced ambition.2 Yet the historical
fact of the cumulative advance of scientific understanding implies that the circularity involved is benign and not vicious.
In assessing the character of science and its achievements, we
need to be sufficiently tinged with postmodernism to be able
to recognise that there is a measure of rational precariousness
involved in its interweaving of theory and experiment, but also
sufficiently tinged with a modernist expectation of intellectual
attainment to be able to do justice to science’s actual success.
The philosophical position that mediates between modernism
1. For a memoir of this period, see J. C. Polkinghorne, Rochester Roundabout,
Longman/W. H. Freeman, 1989.
2. K. Popper, The Logic of Scientific Discovery, Hutchinson, 1959.
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and postmodernism is commonly called critical realism, the
adjective acknowledging the need to recognise that something
is involved that is more subtle than encounter with unproblematic objectivity, while the noun signifies the nature of the
understanding that it actually proves possible to attain.3
I believe that the philosopher of science who has most
helpfully struck this balance has been Michael Polanyi. He
knew science from the inside, since he was a distinguished
physical chemist before he turned to philosophy. In the preface to his seminal book Personal Knowledge, Polanyi wrote,
Comprehension is neither an arbitrary act nor a passive
experience, but a responsible act claiming universal validity. Such knowing is indeed objective in the sense of
establishing contact with a hidden reality . . . Personal
knowledge is an intellectual commitment, and as such inherently hazardous. Only affirmations that could be false
can be said to convey objective knowledge of this kind
. . . Throughout the book I have tried to make this situation apparent. I have shown that into every act of knowing there enters a passionate contribution of the person
knowing what is known, and this coefficient is no imperfection but a vital component in his knowledge.4
These convictions are worked out in great detail in the book,
drawing on Polanyi’s scientific experience in a way that other
scientists can readily recognise as being authentic. He stresses
not only commitment but also the tacit skills involved (for ex3. For more extended treatments of critical realism, see J. C. Polkinghorne,
One World, SPCK/Princeton University Press, 1986, chs 1–3; Reason and Reality,
SPCK/Trinity Press International, 1991, chs 1 and 2; Beyond Science, Cambridge University Press, 1996, ch. 2; Belief in God in an Age of Science, Yale University Press,
1998, chs 2 and 5.
4. M. Polanyi, Personal Knowledge, Routledge and Kegan Paul, 1958, pp. vii–
viii.
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ample, in evaluating the adequacy of theories and in assessing
the validity of experiments in actually measuring what they are
claimed to measure and not some spurious side-effects) that
call for acts of judgement that cannot be reduced to following
the rules of a specifiable protocol. The method of science has
to be learnt through apprenticeship to the practice of a truthseeking community, rather than by reading a manual of technique, for, in a phrase that Polanyi often repeated, ‘we know
more than we can tell’. This role for skilful judgement gives
scientific research a degree of kinship with other human skilful
activities, such as riding a bicycle or judging wine, that require
the exercise of similarly tacit abilities. Though the subject of
science is an impersonal view of the physical world, its pursuit
is an activity of persons that could never be delegated simply to
the working of a well-programmed computer. These personal
acts of discovery are then offered for assessment and sifting
within a competent community, whose judgements are made
with the universal intent of gaining reliable knowledge of the
physical world. The actual character of our encounter with
that world remains the controlling factor. These last points
save the personal knowledge of science from fragmenting into
a loose collection of individual opinions.
I want to add a further note of a theological kind to the
discussion, with the intent of making more intelligible this remarkable ability of scientists to gain such reliable knowledge
of the universe, despite the degree of unavoidable epistemic
precariousness involved in the endeavour. It is a fact of experience that this repeatedly proves possible, even for phenomena
occurring in regimes that are remote from direct human encounter and whose understanding calls for ways of thought
quite different from those of everyday life (quantum theory;
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cosmology)—a fact, incidentally, that undermines the invocation of Darwinian evolutionary process as an all-sufficient explanation. The widespread success of science is too significant
an issue to be treated as if it were a happy accident that we are
free to enjoy without enquiring more deeply into why this is
the case. Critical realist achievements of this kind cannot be a
matter of logical generality, something that one would expect
to be attainable in all possible worlds. Rather, they are an experientially confirmed aspect of the particularity of the world
in which we live and of the kind of beings that we are. Achieving scientific success is a specific ability possessed by humankind, exercised in the kind of universe that we inhabit. I believe
that a full understanding of this remarkable human capacity
for scientific discovery ultimately requires the insight that our
power in this respect is the gift of the universe’s Creator who,
in that ancient and powerful phrase, has made humanity in the
image of God (Genesis 1:26–27). Through the exercise of this
gift, those working in fundamental physics are able to discern
a world of deep and beautiful order—a universe shot through
with signs of mind. I believe that it is indeed the Mind of that
world’s Creator that is perceived in this way. Science is possible because the universe is a divine creation.5
In its turn, theology is not unacquainted with the necessity of circularity. Augustine and Anselm both emphasised the
pattern of ‘believing in order to understand’ as well as ‘understanding in order to believe’. No quest for truth can escape
from the necessity of this hermeneutic circle, linking the encounter with reality to an interpretative point of view, so that
they are joined in a relationship of mutual illumination and
5. Polkinghorne, Belief in God, ch. 1.
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correction. Religious insight is not derived from the unhesitating acceptance of fideistic assertion (as if belief were simply
imposed by some unchallengeable external authority, conveying to us indubitable propositions), but neither can it be based
simply on argument controlled by the conventions of secular thought (such as, for example, the assumption of a purely
naturalistic historicism that what usually happens is what always happens). Theology, as much as science, must appeal
to motivated belief arising from interpreted experience. Of
course, in the case of theology the kind of experience, and the
kinds of motivated beliefs that arise from its interpretation,
are very different from those appropriate to the natural sciences. The latter enjoy possession of the secret weapon of experiment, the ability to put matters to the test, if necessary
through repeated investigation of essentially the same set of
impersonal circumstances. This enables science thoroughly to
investigate a physical regime defined by a definite scale (such
as a given energy range) and to make an accurate map of it.
From this ability arises much of the cumulative character of
scientific understanding, a linear process in which knowledge
increases monotonically. Even in sciences such as palaeontology, where scale is not a controlling factor and significant past
events are not repeatable, evidence accumulates in forms that
remain permanently accessible, to which direct recourse can
be made for further assessment if required.
By way of contrast, in all forms of subjective experience
—whether aesthetic enjoyment, acts of moral decision, loving
human relationships, or the transpersonal encounter with the
sacred reality of God—events are unique and unrepeatable,
and their valid interpretation depends ultimately upon a trusting acceptance rather than a testing analysis. The pattern of
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understanding that results is, so to speak, multidimensional
rather than linear, with no necessary implication of a simple
temporally ordered increase, as if the insights of the present
were inevitably superior in all respects to the insights of the
past. Four distinctive features of religious experience express
the contrast between science and theology in these respects.
First, there is the fact, already noted, that the development of theological understanding is a more complex process
than is the case for scientific understanding. Science achieves
cumulative success, accessible in the present without a continual need to return to the past, so that a physicist today
understands much more about the universe than Sir Isaac
Newton ever did, simply by living three centuries later than
that great genius. In religion, however, each generation not
only has to acquire theological insight of its own and in its
own way, but it also needs to be in a continuing active dialogue
with the generations that have preceded it, lest the specific insights that they attained should be lost. In particular, the adherents of a faith tradition have to remain in permanent contact with that tradition’s unique foundational events. While
contemporary theologians enjoy the opportunities provided
by the particular perspective of today, they need also to seek to
correct any distortion produced by that perspective by being
willing to learn from the complementary insights of earlier
generations. All forms of encounter with deeply personal aspects of reality have to take this historical dimension seriously,
for the character of their understanding is not simply cumulative, and evaluations need to be made in a living relationship
with the past. Just as there is no presumptive superiority of
twenty-first-century music over the music of past centuries,
so there is no necessary superiority in every respect of the
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ideas of the theologians of today over those of the fourth or
sixteenth centuries. Just as philosophical dialogue today continues to engage with the ideas of Plato and Aristotle, in a
similar way the great figures of the theological past—people
such as Augustine, Aquinas, Calvin and Luther—remain necessary participants in contemporary conversation, in a way
that Galileo, Newton and Maxwell are not so directly involved
in the discourse of science. This is because the principal insights of those great scientific pioneers have been incorporated uncontroversially into present textbook knowledge. A
purely contemporary judgement suffices. In the case of theology, however, the competent community within which insights are to be received and assessed is not simply the contemporary academy but it is the Church spread across the
centuries. Hence the role of tradition, not as a straitjacket
imposed a priori on current thinking, but as the indispensable
resource for access to a reservoir of attained understanding
which has continuing significance.
Second, in placing the physical world under scrutiny,
whether by experiment or, in the case of historical sciences
such as cosmology and evolutionary biology, by observation,
the initiative for setting up this encounter with reality lies
with the scientists. In the case of divine reality, however, God
can take the initiative in conveying truth and, in fact, all religious traditions believe that this has happened in occasions of
revelatory disclosure. One of the prime roles played by sacred
scripture in the life of the traditions is to be the record of these
theologically foundational events.6 We have noted already that
6. For more on scripture, see Polkinghorne, Reason and Reality, ch. 5; Science
and the Trinity, SPCK/Yale University Press, 2004, ch. 2.
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for the Christian, basic sources of understanding centre on the
revelation given in the history of Israel and in the life, death
and resurrection of Jesus Christ, a point to which we shall
make repeated return.
Making this second point draws our attention to a third
difference between theology and science. The motivations for
scientific belief arise principally from occurrences that, in
principle, are publicly accessible and repeatable, with the consequence that science succeeds in eliciting virtually universal acceptance for its well-winnowed conclusions. Although
in its modern form science got going in the particular time
and place of seventeenth-century Europe, it has now spread
world-wide. Once the dust has settled in some domain of scientific exploration, the insights that have been gained command universal respect and assent. Hence the unanimity,
within the relevant competent communities, of belief in the
helical structure of DNA and in the quark structure of matter. The religious scene, in contrast, is significantly fragmented. The great faith traditions, such as Judaism, Christianity, Islam, Hinduism and Buddhism, display considerable
enduring stability within their adherent communities. They
all claim to report and nurture human spiritual engagement
with sacred reality, but there is also a perplexing degree of cognitive clash between them concerning detailed belief about the
character of these encounters. These disagreements do not relate only to the defining convictions of the religions (such as
Christian belief in Jesus as the Son of God, or Muslim belief in
the absolute authority of the Qur’an), but they extend also to
general metaphysical understandings. (Time: a linear pilgrim
path, or a samsaric wheel from whose revolutions one needs to
seek release? Human nature: qualities uniquely individual and
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persistent, or recycled through reincarnation?) These clashes
seem to exceed anything that could be explained simply as culturally diverse ways of expressing the same underlying truth.
In this present book, whose purpose is to explore certain aspects of Christian belief and certain practices of Christian
theology, I am not able to do more than acknowledge the challenging and perplexing nature of these interfaith disagreements. Their investigation is an increasingly important and
active item on the theological agenda, but one that cannot be
pursued further on this occasion.7
A fourth point of difference between theology and science relates to the consequences flowing from the embrace of
belief. I am entirely convinced of the existence of quarks and
gluons, but that belief, illuminating though it is in the limited
sphere of elementary particle physics, does not affect my life
in any significant way outside the pursuit of intellectual satisfaction in the study or the laboratory. In contrast, my belief
that Jesus Christ is the incarnate Son of God has consequences
for all aspects of my life, as much in relation to conduct as
to understanding. Religious belief is much more demanding
than scientific belief—more costly and more ‘dangerous’, one
might say. This means that existential factors play a significant
role in the way in which people approach the possibility of religious belief. The motivations that influence its acceptance will
rightly include an assessment of the authentic humanity and
life-enhancing influences to be found in the believing com7. For more on interfaith issues, see the tetralogy: K. Ward, Religion and
Revelation, Religion and Creation, Religion and Human Nature, and Religion and Community, Oxford University Press, 1994, 1996, 1998, and 2000; also J. C. Polkinghorne, Science and Christian Belief/The Faith of a Physicist, SPCK/ Fortress, 1994/1996,
ch. 10.
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munity. No one could suppose that making this assessment is
an unambiguous and straightforward matter. The faiths have
all at times been sources of conflict and oppression (as, of
course, notoriously has also been the case for atheistic beliefs,
such as those expressed in the regimes of Hitler and Stalin).
Yet the faiths have also been sources of much human flourishing and centres of compassionate concern for the needy. In the
case of Christianity, the dreadful history of crusades and inquisitions has to be held in tension with the Church’s record in
pioneering education and healthcare, the inspiration and support that it has given to so much achievement in art and music,
and the work of many Christian people for peace and justice.
There have certainly been ostensibly religious people whose
lives have been denials of the values of the gospel, but there
have also been many Christians whose lives have displayed
outstanding integrity and love. We need to be thankful for
St Francis as well as rightly being ashamed of Torquemada.
These four points of difference imply that the defence
of critical realism is a more subtle matter in theology than it
is in science. The diachronic character of theology, with insight spread across the centuries, deprives it of the simple appeal to manifest monotonic increase in understanding that is
so persuasive in the case of science. Yet development and revision certainly occur in theology, as will be demonstrated by
some of the illustrative material surveyed in the chapters that
follow. Theologians seek to submit their thinking about the
divine nature to being shaped by the character of God’s revelatory self-disclosures, while acknowledging the ineffable element of mystery present in all human encounter with the Infinite. Thus I believe that theology can rightly lay claim to the
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pursuit of truth under the rubric of critical realism. Moreover, it can appeal to a theological argument in support of that
philosophical claim. The God of truth will not be a deceiver,
and insights into the divine character, manifested either in the
works of creation or in the events of revelation, can be relied
upon not to mislead.
Thus, I see there to be a cousinly relationship between
the ways in which theology and science each pursue truth
within the proper domains of their interpreted experience.
Critical realism is a concept applicable to both, not because
there is some kind of entailment from method in one to
method in the other—for the differences in their subject material would preclude so simple a connection—but because the
idea is deep enough to encompass the character of both these
forms of the human search for truthful understanding.
This is a theme that I have often discussed in my writing. Pursuing it requires the analysis of actual examples, rather
than relying on an attempted appeal to grand general principles. In my Terry Lectures I sought to set out five points
of analogy between two seminal developments, one in physics
and one in Christian theology: the exploration of quantum insight and the exploration of Christological insight.8 In making
this comparison, I discerned five points of cousinly relationship between these two great human struggles with the surprising and counterintuitive character of our encounter with
reality. In outline, these five points are:
(1) Moments of enforced radical revision. The crisis in physics that led eventually to quantum theory began with great
8. Polkinghorne, Belief in God, ch. 2.
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perplexity about the nature of light. The nineteenth century had shown quite decisively that light possessed wave-like
properties. However, at the start of the twentieth century,
phenomena were discovered that could only be understood on
the basis of accepting the revolutionary ideas of Max Planck
and Albert Einstein that treated light as sometimes behaving
in a particle-like way, as if it were composed of discrete packets
of energy. Yet the notion of a wave/particle duality appeared
to be absolutely nonsensical. After all, a wave is spread out
and oscillating, while a particle is concentrated and bullet-like.
How could anything manifest such contradictory properties?
Nevertheless, wave/particle duality was empirically endorsed
as a fact of experience, and so some radical rethinking was evidently called for. After much intellectual struggle this eventually led to modern quantum theory.9
In the New Testament, the writers knew that when they
referred to Jesus they were speaking about someone who had
lived a human life in Palestine within living memory. Yet they
also found that when they spoke about their experiences of
the risen Christ, they were driven to use divine-sounding language about him. For example, Jesus is repeatedly given the
title ‘Lord’, despite the fact that monotheistic Jews associated
this title particularly with the one true God of Israel, using it
as a substitute for the unutterable divine name in the reading
of scripture. Paul can even take verses from the Hebrew Bible
that clearly refer to Israel’s God and apply them to Jesus (for
example, compare Philippians 2:10–11 with Isaiah 45:23, and
1 Corinthians 8:6 with Deuteronomy 6:4). How could this
9. For an introduction to quantum theory, see J. C. Polkinghorne, Quantum
Theory: A Very Short Introduction, Oxford University Press, 2002.
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possibly make sense? After all, Jesus was crucified and Jews
saw this form of execution as being a sign of divine rejection,
since Deuteronomy (21:23) proclaims a curse on anyone hung
on a tree. Experience and understanding seemed as much at
odds here as they did in the case of the physicists’ thinking
about light.
(2) A period of unresolved confusion. From 1900 to 1925, the
physicists had to live with the paradox of wave/particle duality
unresolved. Various techniques for making the best of a baffling situation were invented, by Niels Bohr and others, but
these expedients were no more than patches clapped onto the
broken edifice of Newtonian physics, rather than amounting
to the construction of a grand new quantum building. It was
intellectually all very messy, and many physicists at the time
simply averted their eyes and got on with the less troubling
task of tackling detailed questions that were free from such
fundamental difficulties. Problem-solving in normal science
is often a more comfortable pursuit than wrestling with perplexities in revolutionary science.
In the New Testament, the tension between human and
divine language used about Jesus is simply there, without any
systematic theological attempt being made to resolve the matter. It seems that those early generations of Christians were
so overwhelmed by the new thing that they believed that God
had done in Christ, that its authenticity and power were of
themselves sufficient to sustain them without forcing them to
attempt an overarching theoretical account. Yet, the position
taken by those New Testament writers was clearly intellectually unstable, and the issue could not be ignored indefinitely.
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(3) New synthesis and understanding. In the case of physics,
new insight came with startling suddenness through the theoretical discoveries of Werner Heisenberg and Erwin Schrödinger, made in those amazing years, 1925–26. An internally
consistent theory was brought to birth, which required the
adoption of novel and unanticipated ways of thought. Paul
Dirac emphasised that the formal basis of quantum theory lay
in what he called the superposition principle. This asserts that
there are quantum states that are formed by adding together,
in a mathematically well-defined way, physical possibilities
that Newtonian physics and commonsense would hold to be
absolutely incapable of mixing with each other. For example,
an electron can be in a state that is a mixture of ‘here’ and
‘there’, a combination that reflects the fuzzy unpicturability
of the quantum world and which also leads to a probabilistic
interpretation, since a 50–50 mixture of these possibilities is
found to imply that, if a number of measurements of position
are actually made on electrons in this state, half the time the
electron will be found ‘here’ and half the time ‘there’. This
counterintuitive principle just had to be accepted as an article
of quantum faith. Richard Feynman introduced his lectures
on quantum mechanics by talking about the two-slits experiment (a striking example of counterintuitive quantum ambidexterity), concerning which he wrote,
Because atomic behaviour is so unlike ordinary experience, it is very difficult to get used to, and it appears peculiar and mysterious to everyone . . . we shall tackle immediately the basic element of the mysterious behaviour
in its most strange form. We choose to examine a phenomenon which is impossible, absolutely impossible, to explain in any classical way, and which has in it the heart of
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quantum mechanics. In reality it contains the only mystery. We cannot make the mystery go away by ‘explaining’
how it works. We will just tell you how it works.10
The quest for a deeper understanding of the fundamental phenomena recorded in the New Testament, eventually led
the Church to a trinitarian understanding of the nature of
God (Councils of Nicaea, 325, and Constantinople, 381) and
to an incarnational understanding of two natures, human and
divine, present in the one person of Christ (Chalcedon, 451).
These were important Christian clarifications, but one cannot
claim that theology, wrestling with its profound problem of
understanding the divine, has been as successful as science has
been in attaining its understanding of the physical world. The
latter is at our disposal to interrogate and put to the experimental test, but the encounter with God takes place on different terms, involving awe and worship and obedience. There is
an important qualifying theological insight, called apophatic
theology, stressing the otherness of God and the necessary
human limitation in being able to speak adequately of the mystery of the divine nature. There are bounds to the possibilities
of theological explanation. The Fathers of the Church, who at
the Councils had formulated fundamental Christian insights,
would, I believe, have been quite content to echo Feynman’s
words, ‘We will just tell you how it works’.
(4) Continued wrestling with unsolved problems. Even in science, total success is often elusive. Quantum theory has been
brilliantly effective in enabling us to do the sums, and their
10. R. Feynman, The Feynman Lectures on Physics, vol. 3, Addison-Wesley,
1965, p. 7.
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answers have proved to be in extremely impressive agreement
with experimental results. However, some significant interpretative issues still remain matters of uncertainty and dispute. Chief among these is the so-called measurement problem. How does it come about that a particular result is obtained
on a particular occasion of measurement, so that the electron
is found to be ‘here’ this time, rather than ‘there’? It is embarrassing for a physicist to have to admit that currently there is
no wholly satisfactory or universally accepted answer to that
entirely reasonable question. Quantum physics has had to be
content for eighty years to live with the uncomfortable fact
that not all its problems have yielded to solution. There are
still matters that we do not fully understand.
Theology also has had to be content with a partial degree of understanding. Trinitarian terminology, for example
in its attempt to discriminate the divine Persons in terms of
a distinction between begetting and procession, can sometimes seem to be involved in trying to speak what is ineffable.
The definition of Chalcedon, asserting that in Christ there
are two natures ‘without confusion, without change, without
division, without separation’, is more a statement of criteria
to be satisfied if Christological discourse is to prove adequate
to the experience preserved in scripture and continued within
the Church’s tradition, than the articulation of a fully developed Christological theory. Chalcedon maps out the enclosure within which it believes that orthodox Christian thinking should be contained, but it does not formulate the precise
form that thinking has to take. In fact, further Christological
argument, both within the Chalcedonian bounds and outside
them, has continued down the centuries since 451.
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(5) Deeper implications. A persuasive argument for a critical realist position lies in its offering an explanation of how
further successful explanations can arise from a theory, often
concerning phenomena not explicitly considered, or even
known, when the original ideas were formulated. Such persistent fruitfulness encourages the belief that one is indeed
‘on to something’, and that a verisimilitudinous account has
been attained. In the case of quantum theory, a number of
successes of this kind have come to light, including explaining the stability of atoms (their remaining unmodified by the
numerous low-energy collisions to which they are subjected),
and the very detailed calculations of their spectral properties
that have proved to be in impressive agreement with experimental measurements. Strikingly novel, and eventually experimentally verified, predictions have also been made. One
of the most outstanding of these is the so-called EPR effect, a
counterintuitive togetherness-in-separation that implies that
two quantum entities that have interacted with each other remain mutually entangled, however far they may subsequently
separate in space. Effectively, they remain a single system, for
acting on the one ‘here’ will produce an immediate effect on
its distant partner.
Incarnational belief has offered theology some analogous
degree of new insight. For example, Jürgen Moltmann has
made powerful use of the concept of divine participation in
creaturely suffering through the cross of Christ. He emphasises that the Christian God is the crucified God,11 the One
who is not just a compassionate spectator of the suffering of
creatures but a fellow-sharer in the travail of creation. The
11. J. Moltmann, The Crucified God, SCM Press, 1974.
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concept of a suffering God affords theology some help as it
wrestles with its most difficult problem, the evil and suffering
present in the world.
The purpose of this book is to pursue further the analogies between the scientific investigation of the physical world
and theological exploration of the nature of God. This strategy is adopted in the hope that it will encourage those of a
scientific cast of mind to take theological discussion more seriously, and that it will also offer theologians a worked example
of a form of possible approach to theological enquiry of a form
naturally congenial to the scientifically minded, moving from
experience to understanding in a manner that I have called
‘bottom-up thinking’.12 The procedure that I shall follow is
to set up a series of parallels between aspects of exploration
and conceptual development as we find them respectively in
quantum physics and in Christian theology.
12. For an approach to Nicene Christian belief along these lines, see Polkinghorne, Science and Christian Belief/Faith of a Physicist.
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